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# -*- coding: utf-8 -*-
# vispy: gallery 10
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
"""
Show an image using gloo.
"""
import numpy as np
from vispy import app
from vispy.gloo import clear, set_clear_color, set_viewport, Program
# Image
def func(x, y):
return (1-x/2+x**5+y**3)*np.exp(-x**2-y**2)
x = np.linspace(-3.0, 3.0, 512).astype(np.float32)
y = np.linspace(-3.0, 3.0, 512).astype(np.float32)
X, Y = np.meshgrid(x, y)
idxs = func(X, Y)
# Image normalization
vmin, vmax = idxs.min(), idxs.max()
idxs = (idxs - vmin) / (vmax - vmin)
# Colormaps
colormaps = np.ones((16, 512, 4)).astype(np.float32)
values = np.linspace(0, 1, 512)[1:-1]
# Hot colormap
colormaps[0, 0] = 0, 0, 1, 1 # Low values (< vmin)
colormaps[0, -1] = 0, 1, 0, 1 # High values (> vmax)
colormaps[0, 1:-1, 0] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 1.00, 1.00, 1.00])
colormaps[0, 1:-1, 1] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 0.00, 1.00, 1.00])
colormaps[0, 1:-1, 2] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 0.00, 0.00, 1.00])
# Grey colormap
colormaps[1, 0] = 0, 0, 1, 1 # Low values (< vmin)
colormaps[1, -1] = 0, 1, 0, 1 # High values (> vmax)
colormaps[1, 1:-1, 0] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
colormaps[1, 1:-1, 1] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
colormaps[1, 1:-1, 2] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
# Jet colormap
# ...
img_vertex = """
attribute vec2 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0 );
v_texcoord = texcoord;
}
"""
img_fragment = """
uniform float vmin;
uniform float vmax;
uniform float cmap;
uniform sampler2D image;
uniform sampler2D colormaps;
uniform vec2 colormaps_shape;
varying vec2 v_texcoord;
void main()
{
float value = texture2D(image, v_texcoord).r;
float index = (cmap+0.5) / colormaps_shape.y;
if( value < vmin ) {
gl_FragColor = texture2D(colormaps, vec2(0.0,index));
} else if( value > vmax ) {
gl_FragColor = texture2D(colormaps, vec2(1.0,index));
} else {
value = (value-vmin)/(vmax-vmin);
value = 1.0/512.0 + 510.0/512.0*value;
gl_FragColor = texture2D(colormaps, vec2(value,index));
}
}
"""
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, size=(512, 512),
keys='interactive')
self.image = Program(img_vertex, img_fragment, 4)
self.image['position'] = (-1, -1), (-1, +1), (+1, -1), (+1, +1)
self.image['texcoord'] = (0, 0), (0, +1), (+1, 0), (+1, +1)
self.image['vmin'] = +0.1
self.image['vmax'] = +0.9
self.image['cmap'] = 0 # Colormap index to use
self.image['colormaps'] = colormaps
self.image['colormaps'].interpolation = 'linear'
self.image['colormaps_shape'] = colormaps.shape[1], colormaps.shape[0]
self.image['image'] = idxs.astype('float32')
self.image['image'].interpolation = 'linear'
set_clear_color('black')
self.show()
def on_resize(self, event):
width, height = event.physical_size
set_viewport(0, 0, *event.physical_size)
def on_draw(self, event):
clear(color=True, depth=True)
self.image.draw('triangle_strip')
if __name__ == '__main__':
canvas = Canvas()
app.run()
|
